The present invention generally relates to an imaging probe of an imaging catheter. The present invention more specifically relates to mechanically scanned imaging probes for use in, for example, an intravascular ultrasound (IVUS) or intra-cardiac echo-cardiography (ICE) catheter. The present invention still further relates to such an imaging probe wherein the imaging probe is configured to assure efficient and complete fluid flushing from the catheter sheath to preclude formation of air bubbles in the vicinity of the ultrasonic transducer of the imaging probe. In addition this invention relates to imaging probe configuration to ensure the prevention of air bubbles during rotational operation by continuously directing fluid across the imaging probes transmission surface.
IVUS catheters enable the imaging of internal structures in the body. ICE catheters enable the imaging of larger internal structures in the body. Coronary IVUS catheters are used in the small arteries of the heart to visualize coronary artery disease, for example. Coronary ICE catheters are used in the cavity of the heart to visualize structural heart disease, including atrial septal defects (ASD), patent foramen ovale (PFO) and to guide various procedures including septal puctures, percutaneous valvular replacement, and various ablations treatment strategies. To that end, an IVUS or an ICE catheter will employ at least one ultrasonic transducer that creates pressure waves to enable visualization. At least one transducer is usually housed within a surrounding sheath or catheter member and rotated to enable 360 degree visualization. Because air is not an efficient medium for the transmission of the ultrasonic waves produced by at least one transducer, a fluid interface between the transducer and the sheath in which it is disposed is usually provided. Unfortunately, current imaging probe configurations do not always prevent the formation of air bubbles in the fluid in the vicinity of the transducer resulting in compromised performance of the imaging catheter. The present invention addresses this and other issues.